Heat a pan over medium heat. Add 1 ½ tablespoons of the butter to the pan and allow it to melt. Add on 3 cups of the marshmallows and mix until the marshmallows melt. Mix in a few drops of red food coloring. Pour in 3 cups of the rice krispies and mix until the cereal is well combined with the marshmallow. Transfer the rice krispies to a sheet tray that has been sprayed with non-stick spray. Use your hands to press down the rice krispies into a flat layer.
Heat a different pan over medium heat. Add 1 ½ tablespoons of the butter to the pan and allow it to melt. Add on 3 cups of the marshmallows and mix until the marshmallows melt. Mix in a few drops of blue food coloring. Pour in 3 cups of the rice krispies and mix until the cereal is well combined with the marshmallow. Transfer the rice krispies to a sheet tray that has been sprayed with non-stick spray. Use your hands to press down the rice krispies into a flat layer.
Use a star cookie cutter to cut out stars from the red and blue trays.
Transfer the marshmallow cream to a piping bag fitted with a circle tip.
Take one of the blue stars and pipe the marshmallow cream on top of it.
Top the marshmallow cream with a red star.
Repeat steps 5 and 6 to finish the remaining star bars.